User defined language custom comment identifier placebrowsing

I have defined a custom language (for PPCL) and the comment line in this is after few characters away from the beginning of the line. A sample is here
E 1999 C : ON(EXHAUST FAN SERVICE POINT)
ET 2000 ON("%Z%SYS")
ET 2005 C : IF(EXHAUST FAN SERVICE POINT OFF) THEN GOTO SHUTDOWN

The position of comment identified is always on the 13th character from the start of the line. The position of C.